Deciphering the specificity and function of FGD RhoGEFs during skin development

形态发生是指在发育中的组织中发生的所有细胞重排，这些重排允许生物体获得其适当的和特征性的形状。到目前为止，控制胚胎发育这一关键步骤的分子机制仍然知之甚少。Rho GTP酶家族的分子由于其支配细胞结构的能力而成为形态发生的关键调节因子。在哺乳动物中，有20种Rho GTP酶和超过150种调节剂是RhoGEF，RhoGAP和RhoGDI家族的一部分。尽管如此，这些复杂的信号网络中只有少数分子得到了深入研究。这使我们无法全面了解Rho GTP的作用。考虑到所涉及的复杂性以及研究这些分子在动物模型中的作用以充分掌握其生物学功能的重要性，开发比经典遗传小鼠模型劳动密集度更低的方法至关重要。 小鼠皮肤是研究形态发生过程的理想系统，因为它是通过一系列复杂的细胞重排发育的，但这些过程的分子细节仍然知之甚少。我最近利用了一项新技术，通过将慢病毒颗粒注射到活小鼠胚胎的羊膜腔中，使皮肤祖细胞发生遗传转化。使用这种技术，我开发了一种高通量的筛选方法，允许识别的几个新的监管机构的皮肤形态之间的Rho GTPases信号网络。有趣的是，RhoGEFs的FGD家族中的3个成员，即FGD 1，FGD 2和FGD 5，是发现的候选人之一。这些分子已被证明可以激活细胞中的Rho GTP酶，但其生物学功能尚不清楚。我假设FGD1，FGD2和FGD5通过与特定效应蛋白的相互作用各自调节皮肤发育的不同方面。使用最先进的多学科方法，如慢病毒注射，细胞成像和蛋白质组学，这个NSERC研究计划将专注于了解FGD RhoGEFs在皮肤形态发生过程中的作用。这项工作将为调节皮肤发育的分子机制提供基本的见解，这将是对这些分子在该组织中的功能的首次分析。此外，这项工作将有助于我们了解个体Rho GTP酶在胚胎发育过程中如何协调细胞行为。

Morphogenesis refers to all the cellular rearrangements occurring in a developing tissue that allow an organism to acquire its proper and characteristic shape. To this date, the molecular mechanisms that govern this crucial step of embryonic development are still poorly understood. Molecules from the Rho GTPases family are rising as key regulators of morphogenesis due to their ability to govern cellular architecture. In mammals, there is 20 Rho GTPases and more than 150 regulators that are part of the RhoGEFs, RhoGAPs and RhoGDIs families. Still, only a few molecules from these intricate signaling networks have been studied in depth. This is preventing us from appreciating the full scope of Rho GTPases roles. Given the large complexity involved and the importance of studying the role of these molecules in an animal model to fully grasp the extent of their biological functions, it is essential to develop methods that are less labour intensive than classic genetic mouse models. The mouse skin is an ideal system to study morphogenesis processes since it develops through a succession of sophisticated cellular rearrangements, but the molecular details of these processes remain poorly comprehended. I recently took advantage of a new technology that allows the genetic transformation of skin progenitors via the injection of lentiviral particles in the amniotic cavity of living mouse embryo. Using this technique, I developed a high-throughput screening methodology that permitted the identification of several new regulators of skin morphogenesis among the Rho GTPases signaling networks. Intriguingly, 3 members of the poorly characterized FGD family of RhoGEFs, namely FGD1, FGD2 and FGD5, were among the candidates uncovered. These molecules have been shown to activate Rho GTPases in cells but their biological functions are unknown. I hypothesize that FGD1, FGD2 and FGD5 each regulates different aspects of skin development through their interaction with specific effector proteins. Using state-of-the art multidisciplinary approaches such as lentiviral injection, cell imaging and proteomic, this NSERC research program will focus on understanding the role of FGD RhoGEFs during skin morphogenesis. This work will provide fundamental insights into the molecular mechanisms that regulate skin development and it will be the first analysis of the function of these molecules in this tissue. Additionally, this work will contribute to our knowledge of how individual Rho GTPases coordinate cellular behaviors during embryonic development.